Gov. Jerry Brown’s office has asked the San Bernardino County District Attorney’s Office to respond to claims from Kevin Cooper’s attorneys, seeking new DNA tests in their effort to win clemency for their client, convicted and sentenced to death for a 1983 Chino Hills quadruple murder.

Cooper’s attorneys earlier this month sent Brown’s office for review a 34-page response, plus attachments, to questions from the governor’s office regarding Cooper’s claim of innocence and need for a more recently developed DNA test that they believe will exonerate him.

The last series of DNA tests in the case, in 2002, concluded Cooper was the killer, but his attorneys have continued to dispute that.

San Bernardino prosecutors have said Cooper’s claims are empty, and previously filed a 94-page document with the governor’s office that preceded its formal request for both sides to answer questions about the case. The governor’s office letter dated Aug. 29 asks the District Attorney’s Office to respond by Oct. 11.

Documents from both sides will be used by the governor’s office to evaluate whether the tests sought by Cooper are warranted.

The June 4, 1983, attack for which Cooper was convicted in 1985 took the lives of Doug and Peggy Ryen; their 10-year-old daughter, Jessica; and neighbor Christopher Hughes, 11, who was staying overnight at the Ryens’ home.

The boy was a friend of the Ryens’ 8-year-old son, Joshua, who survived the attack with a slashed throat.

Cooper, 60, has exhausted all appeals. California’s death penalty remains on hold while its procedures are reviewed in court cases.